Compound pneumatic impact-tool



W BURLINGHAM.

COMPOUND PNEUMATIC IMPACT TOOL.

APPLICATION FILED OCT. 15. m5.

1 ,344, 1 7'0. I te ted J 1111 22, 1920.

4 SHEETS-SHEET1.

INVENTOR r W. BURLINGHAM. COMPOUND PNEUMATIC IMPACT TOOL.

4 SHEETS-SHEET 2.

ATTORNEYS INVENTOR a N \n m. w L: x. [J HM N WW Q a W E Q! 1 I i N 5 \m. MN WM M y 3 W W. BURLINGHAM.

COMPOUND PNEUMATIC IMPACT TOOL.

APPLICATION HLED OCT. 15, 1915.

1 344 170 PatentedJune 22,1920.

WITNESSES Q INVENTOR- ATTORNEYS *W. BURLINGHAM. COMPOUND PNEUMATIC IMPACT TOOL.

APPLICATION FILED OCT- I5, 1915- O 0 B 2 94 M 1T R 9 m XI T H F u 2 M n m W. Z

WITNESSES UNITED" STATES PATENT OFFICE.

VIRGINIA.

Application filed October 15, 1915.

To all whom it may concern:

Be it known that '1, WILLIAM BURLING- HAM, a citizen of the United States, residing at Newport News, in the county of \Varwick, State of Virginia, have invented a new and useful Compound Pneumatic Impact-Tool, of which the following is a specification.

In large industrial plants, such as ship ceiver through a novel'arrangement of ports and passages, so that I am enabled to utilize to a m Ximum extent the expansive effect of the motive fluidwhich is initially used at high pressure, and I am further enabled to simultaneously employ high pressure live motive fluid and low pressure motive fluid to augment the velocity or momentum of the hammering plunger prior to or during the act of striking its blow directly upon the shank. of the workingtool.

To the above ends, my invention consists of a'novel construction ofa compound pneumatic impact tool'in which the fluid'distribution system is controlled by a single valve located in the piston chamber andthrough which the piston passes, said piston impacting its blow directly upontheshank of a working tool insertedin the barrel.

The plunger is actuatedby compressed air or other motive fluid, and my novel construction of impact tool is especially adapted to be employed in connection with riveting, chipping, calking, hammering and similar operations wherein a hammer and chisel have heretofore been employed.

In devices of this character, it is desirable to have the length of the tool as short as possible relativelyto the length offstroke which it is necessary to give the pistonin Specification of Letters Patent.

diameter,

VIRGINIA, ASSIGNOR TO ENGINEERING NEWS, -VIRGINIA, A CORPORATION OF COMPOUND PNEUMATIC IMPACT-TOOL.

Patented June 22, 1920. Serial No. 56,002.

order that the piston acts with sufficient power upon the working tool, while it is desirable that the piston have a considerable weight and as long a stroke as possible, it is alsodesirable in devices of this character, that the entire tool shall not be of eXcessive and it is therefore preferable to lengthen the piston rather than to increase its diameter.

For the purpose of illustrating my invention, I have shown in the accompanying drawings certain forms thereof which are at present preferred by me, since the same will be found in practice to give satisfactory and reliable results, understood that the various instrumentalities of which my invention consistscan be variously arranged and organized and that my invention is not limited to the precise arrangement and organization of these instrumentalities as herein shown and described.

Figure 1 represents a sectional elevation of a pneumatic impact tool embodying my invention.

Fig. 2 represents a sectionalelevation of a pneumatic impact tool with the handle removed.

Fig. 3 represents a bottom planview of the valve casing with the bottom removed.

Fig. 4 represents a diagrammatic view of the barrel, piston, valve mechanism, and

passages, illustrating the parts in their respective positions when the piston is at the beginning of its stroke.

Fig. 5 represents a diagrammatic View similar to Fig. 4, but showing the positions which the parts assume when the piston is at the end of its forward stroke.

Fig. 6 represents a section on line iv-a: Fig. 1.

' Fig. 7 represents a perspective view of a piston embodying my invention.

F ig. 8 represents a perspective view of the valve, in detached position.

Fig. 9 represents a transverse section of the valve casing.

Fig. 10 represents a top plan view of the barrel or tool casing.

Fig. 11 represents a top plan viewof the valve casing bottom. F 'g. 12 represents a sectional view device;

of my Fig. 13 represents a top plan view of the valve casing.

Similar numerals of reference indicate corresponding parts in the figures.

Referring to the drawings 1 designates the barrel or casing of a pneumatic impact tool embodyingmy invention. 2 designates the axial bore which is of cult rged diameter at its forward end and forms a low pressure cylinder or piston chamber 5, the forward end of which is partially closed by means of a tool socket l illustrated in the present instance as being in threaded engagement therewith and pro-.

vided at its inner end with an annular recess 5. This tool socket t is adapted to receive the shank of the working tool, such as for example a rivet set, chisel, calking tool or other percussion tool. The inner end of the bore 2 has a reduced diameter and forms a high pressure cylinder or piston chamber 6. 7 designates an external shouldeer on the barrel 1 with which engages a shoulder 8 of a sleeve the outer periphery of which has its inner end threaded or otherwise adapted to interlock with the sleeve 10 of the handle 11, which latter may be a pistol grip, or closed, or of any other conventional type, and is provided with an inlet or pressure supply duct 12 adapted to be con nected with the flexible hose, not shown, leading from the source of motive fluid supply. The handle is provided with a springpressed valve 13 which is manually actuated by means of a lever 1 1-, whereby admission of live motive fluid to the passage 15 is con trolled, as desired.

16 designates ring or collar surrounding the barrel 1 and keyed thereto, said ring being interlocked with the sleeve 9 and maintained in locked position by means of a spring clip 17, which interlocks with said band and said sleeve. 18 designates a combined high and low pressure piston, which comprises a cylindrical bolt having at its forward end spaced annular flanges forming the low pressure piston 15). The piston terminates at its forward end in the striker 20, which may be of reduced oiameter, if desired. The piston is provided with an annular groove 21 located intermediate the ones thereof and the rear end of the piston is preferably slightly rounded or cut away, in order that the motive fluid may the more readily pass in rear of the piston to effect its initial advance.

The rear end of the barrel 1 has seated thereagainst the bottom 22 of a valve casing 23 which is retained in assembled position by means of the handle 11 and its adjuncts. The valve casing 23 is apertured to receive a reciprocatory valve 24: consisting of a cylindricalshell. the forward end of which is adapted to extend into an aoertured annular flange 25 on the valve box bottom 22.

The chamber within the valve 24: forms a continuation of the high pressure chamber or cylinder 6, which latter is of uniform diameter in order that the piston 18 may reciprocate therethrough.

The outer periphery of the valve 21 is provided with annular grooves 26, 27 and 28. The forward end of the valve 2st has an enlarged diameter 29 which reciprocates in a recess 30 in the valve casing, and is provided at its forward end with an annular groove 31, thereby forming an inner flange 32 which is guided by the walls of the flange 25 of the valve box bottom during the cycle of the operation. The rear end of the valve forms a cylindrical extension which controls admission of live motive fluid through the ports 33, which communicate by means of the annular port 845 in the handle with the motive fluid inlet passage The construction and arrangement of the per s and passages through which the motive fluid passes to effect the reciprocation of the hammering piston can be best described by reference to the passage of the motive fluid during the cycle of the operation.

Assuming that the various parts are in the position seen in Figs. 1 and 4, the live motive fluid passes through ports 34, ports 33 around the inner cylindrical end 35 of the valve and into the high pressure cylinder (3 in rear of the piston 18 to cause it to move forwardly. The barrel 1 is provided with a desired number of receivers 36, and as the pressure of the live motive fluid is exerted against'the rear end of the high pressure piston 18, the motive fluid which has been stored in the receivers 36 during the previous cycle of the operation, as will be hereinafter clearly set forth, passes from the receivers 86, through the passages 37 to the annular port 38, thence through the passage 39 to the annular port 40 and therefrom through the passages 11 to the low pressure cylinder 3 in rear of the low pressure piston 19, to effect the forward movement of the combined high andlow pressure piston so that the latter advances from the position seen in Fig. 1 to that seen in Fig. 5. The motive fluid in the low pressure cylinder in front of the low pressure piston 19 escapes to the atmosphere through passages 12, annular ports 43, 4A and 30 and the main exhaust passage which leads through the valve casing and the barrel 1 and communicates with the atmosphere, as will be best understood by reference to Figs. 1 and 4r.

As soon as the rear end of the piston 18 uncovers the port 46, live motive fluid will pass through said port and through the passage 47 and acting upon the enlarged pressure area at the forward end of the valve, the position of the valve will be reversed, and the valve will move from the position seen in Fig. 4 to that seen in Fig. 5, it being understood that at this time the port 48 which also communicates with the passage 47 is closed by the piston 18. The port 46 is arranged with respect to the port48 so that the valve 24 will move rearwardly prior to the uncovering by the piston of the port 49 which leads to the passage 50 of the receiver 36, so thatthe motive fluid cannot pass from the receiver throiigh passage 37 until the valve has moved forwardly during the next cycle of operation. The valve and the piston are now in the position seen in Fig. 5, and as soon as thevalve 24 is movedrearwardly to its position seen in Fig. 5, the expanded motive fluid which has been used to advance or move forwardly the piston passes through the port 51 in the handle and passage 52 in the handle and valve casing to the annular port 53 and through the annular port 54 to the annular port 43, thence through the passage 42 into the low pressure cylinder 3 in advance of the low pressure piston 19. This equalizes the pressure in the high and the low pressure cylinder and due to the greater pressure area of the piston 19, the combined high and low pressure piston will be returned to its initial position at the rear of the piston chamber,

as seen in Fig. 4. On the rearward stroke of the piston, as soon as the annular groove 21 registers with the port 48, the motivefluid is free to exhaust. from beneath the valve through passage 47 and port 48 around the annular groove 21 of the piston and then to the atmosphere through port 55 and passage 56, the construction of which latter will be best understood by reference to Fi 6. As soon as the pressure in front of the valve is released, the live motive fluid exerted against the rear end of the valve causes it to be moved into its, forward position seen in Figs. 1, 2 and 4. The exhaust from the low'pressure cylinder 3 in rear of the low pressure piston 19 on the rearwardimovement thereof takesplace through the passage 41, annular port 40, annular ports 57 and 58 and the exhaust passage 59, which leads through the. barrel 1 and the sleeve 10 of the handle.

I preferably employ a plurality of receivers and form the same in both the valve casing and the barrel. The valve casing may be economically manufactured by cutting away a portion of a block or body portion 60 and then shrinking a sleeve 61 thereover. The body portion 60 carries the dowels 62 which pass through apertures 63 in the valve box bottom 23 and into apertures 64 in the end of the barrel in order to interlock such parts. The rear end of the body portion 60 of the valve casing has an aperture 65 with which interlocks a dowel pin 66 carried by the handle, see Fig. 1, so that the handle, valve mechanism and barrel are maintained in proper alinement. The side walls of the valve are imperforate and the grooves form the external rings 67, 68, 69, 70 and 29, while the internal bore is of substantially the same diameter in order that the piston may travel theret-hrough.

It is also within the scope of my invention to employ a piston corresponding to that seen incFig. 7, wherein the striker or impact portion 71 is extended beyond the diflferential piston 72 to a greater distance than in the'piston seen in the other figures. The piston seen in Fig. 7 is the same in construction except for the extension at the forward end and a further description thereof is therefore believed to be unnecessary.

The manner of interlocking the ring 16 with the barrel isshown in Fig. 12 wherein a key 73 is seated in a recess 74 in the barrel 1 and interlocks with the walls of one of the slots 7 5 in the ring 16.

It will be apparent from the foregoing that the expanded motive fluid passes from the high pressure cylinder to the low pressure cylinder to effect the return of the pis ton and the expanded motive fluid in the high pressure cylinder also fills the receiver and effects the reverse of the valve. The forward movement of'the piston is effected by pressure of live motive fluid against the rear end of the high pressure piston and also by means of the expanded motive fluid stored in the receiver acting against the low pressure piston. The passage of the expanded motive fluid from the high pressure cylinder to the receiver is controlled by the piston; The passage of the motive fluid from the receiver to the low pressure piston is controlled by the valve as is also the exhaust from the low pressure cylinder. The passage of motive fluid from the high pressure cylinderto effect the return of the piston controlled by the valve.

The first outward. stroke of the hammering piston is due solely to pressure of live motive fluid on the high pressure piston. The second and all succeeding outward or forward strokes of the piston are augmented by the energy due to the air from the receiver acting on the low pressure piston. It will thus be seen that high and low pressure motive fluid simultaneously cooperate to augment the forward stroke of the piston. The only exhaust is of low pressure motive fluid which has directly and expansively performed its function, thereby enabling one to obtain a very high efficiency, as is evident.

As the hammering piston is returned by the expanding live motive fluid acting 5 against differential pressure areas, the return stroke'of the piston is cushioned and the shock and vibration of the tool are materially reduced.

Special attention is directed to the fact that the cylindrical hollow valve is located in the piston chamber and adapted to have the piston preferably pass substantially through it, and in the form illustrated the high pressure portion of the piston passes into and substantially through the valve. By arranging the valve in alinement with the piston and having the latter pass through the valve, I am enabled to employ a piston chamber of greater length without increasing the length of the entire tool. This permits a greater length of stroke of the piston in a tool of a given length with consequent increase in the power of the tool.

I am aware that it has heretofore been proposed to use compressed air somewhat as in a compound engine in rock drills or similar structures, which employ massive and heavy reciprocating engines frequently weighing several hundred pounds, and which are required to be supported upon a suitable tripod, and wherein the drill or other working tool is connected to or reciprocates directly in unison with the reciprocating piston. My present invention is, however, clearly differentiated from massive tools of this character having a comparatively slow moving piston, for the reason that my present device is particularly applicable to the small, manually held and manually controlled riveters or chipping tools, wherein the tool is usually supported in the hands of the operator only, and wherein the hammering piston reciprocates with great rapidity and impacts directly upon the shank of the chisel, rivet set or other working tool.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A pneumatic impact tool, comprising a barrel, a small diameter cylinder therein, a large diameter cylinder, a piston adapted to reciprocate in said cylinders, a single valve for controlling the distribution of motive fluid and through which said piston passes, and means coacting with said single valve to utilize the energy left in the motive fluid after it has been initially used in one cylinder to augment the energy of said piston.

52. A pneumatic impact tool, comprising a barrel, a large diameter cylinder therein, a small diameter cylinder, a reciprocatory piston in said cylinders having differential pressure areas, the sum of the pressure on the rear working faces of the piston causing the striking blow, the difference of pressure on opposite extremities of said piston efl'ecting the return thereof, and a single valve controlling the air distribution to and from said cylinders and through which said piston passes.

3. A pneumatic impact tool, comprising a barrel having its forward end open to re ceive the shank of a working tool and pro vided with cylinders of different diameters, a piston of varying diameter conforming to said cylinders, a receiver, and a single valve in alinement with said piston and through which said piston passes and effecting the entire distribution of motive fluid to and from said cylinders.

at. A pneumatic impact tool, comprising a barrel, cylinders, therein, a reciprocatory piston in said cylinders, a receiver formed in said barrel exteriorly of said cylinders, and a single valve for controlling the flow of motive fluid to and from said cylinders and into and from said receiver and through whichsaid piston passes during the cycle of the operation.

5. A pneumatic impact tool, comprising a barrel, cylinders therein, a piston in said cylinders, a receiver formed in said barrel, and a single valve for controlling the flow of the motive iiuid to and from said cylinders and into and from said receiver, said piston passing through said valve, and said single valve being operated in one direction by motive fluid at substantially the receiver pressure.

6. A pneumatic impact tool, comprising a barrel, cylinders therein, a reciprocatory piston in said cylinders, a receiver formed in said barrel, a single valve controlling the flow of the motive fluid'to and from said cylinders and into and from said receiver, said valve being operated in one direction by the motive fluid at substantially the receiver pressure and in the opposite direction by constant live air pressure, and said valve being adapted to have the piston pass through it.

7. A pneumatic impact tool, comprising a small diameter cylinder, a large diameter cylinder, a small diameter and large diameter piston adapted to reciprocate in said cylinder, a receiver connected to receive expanded motive fluid from the small diameter cylinder, and a single valve through which the small diameter piston passes and adapted to control the flow of live motive fluid from said small diameter cylinder and the flow of expanded motive fluid from said large diameter cylinder.

8. A pneumatic impact tool, comprising a plurality of cylinders of varying diameters, pistons of varying diameters fitted to reciprocate in said cylinders, a receiver connected to receive expanded motive fluid from the small diameter cylinder, passages adapted to connect said receiver with an end of said large diameter cylinder, and a single valve adapted to have one of said pistons pass through it, and adapted to control the flow of live motive fluid to said small diameter cylinder.

9. A pneumatic impact tool, comprising a small diameter cylinder and a large diameter cylinder, a piston having a small and a small diameter and a large diameter cylinder, a piston having a small diameter and.

large diameter respectively reciprocable in said cylinders, a receiver having a passage leading to it from the forward portion of the small diameter cylinder, and a single valve through which the small diameter of the piston passes, said valve controlling the flow of live motive fluid to the inner end of the small diameter cylinder and the How of expanded motive fluid from the receiver to the inner face of the large diameter of the piston.

11. A pneumatic impact tool, comprising a barrel, a small diameter high pressure cylinder, a large diameter low pressure cylinder, a piston having .a small diameter and large diameter portions respectively rec procable in said cylinder, a receiver, a single alve through which the small diameter of said piston passes, said valve being connected to intermittently admit live motive fluid at the inner end of the high pressure cylinder and to intermittently admit expanded motive fluid from said receiver to an end of saidlow pressure cylinder to drive said piston outwardly, and said valve havlng constant fluid pressure on an end thereof.

12. A pneumatic impact tool, comprising a barrel, small diameter and large diameter cylinders therein, a piston having small and large diameter portions respectively reciprocable in said cylinders, a receiver in said barrel connected to the outer portion of the small diameter cylinder to receive expanded motive fluid from the latter, a valve chamber connected to the forward end of the large diameter cylinder and to the inner end of the small diameter cylinder, and a single valve in said valve chamber located in alinement with the piston and through which the small diameter portion thereof passes and adapted to control the distribution of motive fluid to said small cylinder and expanded motive fluid from the small diameter cylinder to said receiver and thence to the large diameter cylinder.

18. A pneumatic impact tool, comprising a barrel, small diameter and large diameter cylinders therein, a piston having small and large diameter portions respectively reciprocable in said cylinders, a receiver in said barrel connected to the outer portion of said small. diameter cylinder to receive expanded motive fluid from the same and distribute it to said large diameter cylinder, a single valve chamber connected tothe inner andouter ends of said large cylinder, asingle valve reciprocable in said chamber to intermittently admit motive fluid at the inner end, of said small diameter cylinder and to intermittently connect the inner ends of said f large diameter cylinder to exhaust, and said alve being adapted to have the small diameter portion of said piston travel therethrough.

14. A pneumatic impact tool, comprising a barrel, small diameter and large diameter cylinders therein, a piston having small and large diameter portions respectively reciprocable in said cylinders, a receiver in said barrel having a passage to it from the outer portion of-said small diameter cylinder, a

single valve chamber having an inlet for the motive fluid and ports connected to the inner ends of said cylinders and an exhaust, and a single valve in said valve: chamber adapted to admit motive fluid to the small diameter piston and expanded motive fluid fromthe receiver to the inner portion of the large diameter piston and intermittently connect the inner end of thelar'ge diameter cylinder to an exhaust, said valve being adapted to have the small diameter portion of said piston travel therethrough and being actuated in one direction by constant pressure and in the opposite direction by motive fluid which has driven said piston outwardly. g v

15. A pneumatic impact tool, comprising a barrel having cylinders of different diameters, a piston having portions thereof of different diameters to reciprocate in said cylinders, a single valve through which one of the diameters of the piston travels, and adapted to permit motive fluid to act simultaneously upon the small and large areas of said piston, whereby said piston acts as a tandem pistonin striking a blow, and said valve also effecting the equalization of pressure 011 each end of said piston, whereby the preponderance of pressure upon the larger of the differential areas of said piston effects the return of the latter.

16. A pneumatic impact tool, comprising a barrel, high pressure and low pressure cylinders therein, a grooved piston located in said cylinders, a valve chamber, a receiver in said 'barrel, anda single valve in said chamberthrough which said piston travels, said valve controlling ports communicating with said cylinders, valve chamber, and receiver, and actuated in one direction by constant live airpressure upon one end thereof and intermittent live air pressure upon the other end thereof, and saidpiston having a groove permitting exhaust from one end of said valve.

17. A pneumatic impact tool, comprising a barrel, high pressure and low pressure cyl-- inders therein, a grooved piston in said cylinder having a small diameter portion and a large diameter portion, a receiver communicating with said cylinders, and a single differential valve therein through which said piston travels, said valve controlling ports communicating with said cylinders, valve chamber, and receiver, said piston acting on its outward stroke as a tandem piston and on its inward stroke as a differential piston, the inward stroke of said piston being effected by a preponderance of pressure on the large area of said piston, and the groove in said piston permitting exhaust from the larger end of said valve.

18. A pneumatic impact tool, comprising a barrel, a hammering piston therein, a receiver in said barrel, a valve chamber, a single valve in said valve chamber and through which said piston passes and provided with a plurality of grooves, means for introducing constant pressure on one end of said valve, means controlled by said piston for permitting intermittent pressure and exhaust upon the opposite end of said valve, and said valve controlling the passage of expanded air to said receiver and therefrom to act on said piston.

19. A pneumatic impact tool, comprising a barrel having a piston chamber, a grooved hammering piston therein, a receiver in said barrel and communicating with. said chamber, a valve chamber, a single valve in said valve chamber through which said piston travels and provided with a plurality of grooves, means for introducing constant pressure on one end of said valve, said valve controlling the distribution of expanded air to said receiver and therefrom to said chamber, and means controlled by said piston for permitting intermittent pressure and exhaust on the opposite end of said valve.

20. A pneumatic impact tool, comprising a barrel, high and low pressure cylinders therein, a hammering piston having high and low pressure areas thereon, a receiver carried by said barrel and connnunicating with said cylinders, a valve chamber, a single valve therein controlling such communication and provided on its periphery with a plurality of grooves and rings, said valve being hollow and adapted to have the piston travel therethrough, means for introducing constant pressure upon one end of said valve, and means for permitting intermittent pressure and exhaust on the opposite end of said valve.

521. A pneumatic impact tool, comprising a cylinder, a piston therein, a single valve in said cylinder and through which said piston travels, a receiver, means tot effect the expansion of air in said cylinder and distribute it to said receiver, and means to aid in operating said piston by means of the pressure of the expanded air in said receiver.

22. A pneumatic impact tool, comprising a cylinder, a piston therein, a hollow cylindrical valve through which said piston travels, a receiver, means to distribute expanded air from said cylinder to said receiver, and

'means for operating said piston by the prescylinder for augmenting the energy of said piston. I

24. In a compound pneumat1c nnpact tool, a small dlameter cylinder, a large diameter cylinder, small diameter and large diameter pistons adapted to reciprocate in said cylinders, a hollow valve through which the small diameter piston travels, and means controlled by said valve for using the energy left in the motive fluid after it has been used in any of the cylinders for augmenting the blow of said pistons.

25. In a compound pneumatic impact tool having its forward end open, a plurality of cylinders of varying diameters, pistons of varying diameters adapted to fit said cylinders, a hollow valve through which one of said pistons travels, and means controlled by said valve for utilizing the remainder of the energy left in the expanded air after it has been exhausted from the initial pressure cylinder to increase the energy of the stroke or the piston without increase of consumption of the live air.

26. In a compound pneumatic impact tool, a small diameter and a large diameter cylinder portion, a small diameter and a large diameter piston respectively reciprocable in said cylinder portion, a receiver, and a hollow distributionvalve through which one of said pistons travels, said small diameter cylinder portion having passages near its outer end connected at intervals to said receiver by one of said pistons.

27. In a compound pneumatic impact tool, a small diameter and a large diameter cylinder portion, a small diameter and a large diameter piston in said cylinder portion, a receiver, a valve chamber, and a single hollow distribution valve in said chamber in alinement with said piston and through which said piston travels, said small diameter cylinder portion. having a passage near its outer end connected at intervals to said receiver, and having a passage connected to one end of said valve by said piston, the opposite end of said valve having constant pressure thereon.

28. In a compound pneumatic impact tool, a plurality of working cylinder portions of different diameters, pistons of different diameters reciprocable in said cylinder portions, a single valve through which one of said pistons passes, means controlled by said valve for admitting motive fluid to a small diameter cylinder portion, receivers, means for admitting expanded motive fluid from said small diameter cylinder portion to such receivers, and means controlled by said valve for admitting expanded motive fluid from said receivers to the large diameter piston.

29. In a compound pneumatic impact tool, a small diameter and a-large diameter cylinder portion, a large diameter and a small diameter piston reciprocable in'said cylinder portions, a receiver, a single hollow valve through which one of said pistons travels, means controlled by said valve for intermittently admitting motive fluid into the small diameter cylinder portion, means controlled by said piston for alternately admitting expanded motive fluid from the small diameter cylinder portion to the receiver, and means controlled by said valve for equalizing the pressure of the motive fluid, remaining in the small diameter cylinder after the receiver has been filled with motive fluid, between the small diameter cylinder and the space in front of the large piston.

80. In a compound pneumatic impact tool, a working cylinder formed of a small diameter portion and a large diameter por- .tion, a small diameter and a large diameter piston slidable in said cylinder portion, a single hollow valve in alinement with said piston and through which one of said diameters travels, means controlled by said valve for admitting motive fluid to said small diameter cylinder portion, a receiver, means controlled by said piston for admitting expanded fluid from said small diameter cylinder portion to said receiver, and means connected to cooperate with the motive fluid admitting means to simultaneously admit expanded fluid from said receiver in rear of the large diameter piston.

31. In a compound pneumatic impact tool, a barrel having a differential piston chamber forming high pressure and low pressure cylinders, a piston therein having high pressure and low pressure areas, a re ceiver, a single hollow valve through which said piston travels, and means controlled by said valve for simultaneously utilizing live motive fluid on the high pressure area'of said piston and expanded motive fluid from said receiver upon a large area of said piston to drive the latter outwardly.

32. In a compound pneumatic impact tool, a small diameter and a large diameter cylinder portion, a large diameter and a small diameter piston reciprocable in said cylinder portion, a hollow valve in alinement with said piston and through which it travels, means controlled by said valve for intermittently admitting motive fluid into the small diameter cylinder portion, a receiver, means controlled by said piston for conducting the expanded motive fluid exhausted from the small diameter cylinder portion to said receiver, and means controlled by said valve for alternately admitting expanded fluid from said receiver to an end of the large diameter cylinder portion.

33. In a compound pneumatic impact tool, a small diameter and a large diameter cylinder portion, a small diameter and a large diameter piston reciprocable in said cylinder portion, a hollow "alve in alinement with said piston and through which one of the diameters of said piston travels, said valve intermittently admitting the motive fluid into said small diameter cylinder portion, a receiver, means controlled by said piston for conducting expanded fluid from said cylinder portion to said receiver, means connected to the motive fluid admitting means to simultaneously admit expanded fluid from the receiver to the large diameter-cylinder portion in rear of the piston therein, and means controlled by said valve for connecting the opposite end of the cylinder portion to admit of expanded fluid acting differentially against said piston.

34. In a compound pneumatic impact tool, a small diameter and a large diameter cylinder portion, the latter having an opening for the shank of the working tool, a small diameter and a large diameter piston reciprocable in said cylinder portion, passages connected to opposite ends of said cylinder portion, a ieceivei', and a hollow controlling valve in alinement with said piston and through which it travels and arranged to intermittently connect said passages and also to control the exhaust from said large diameter piston, said valve also controlling the distributionof expanded air from the small diameter cylinder portion to said receiver and thence to said large diameter cylinder portion.

35 In a compound pneumatic impact tool, a small diameter and a large diameter cylinder portion, a small diameter and a large diameter piston reciprocable in said cylinder portions, a receiver, a passage from near the outer end of said small diameter cylinder portion to said receiver, a hollow valve in alinement with the piston and through which one of the diameters'thereot travels, said valve intermittently admitting motive fluid to the small diameter cylinder portion, and a passage from said receiver to the inner end of the large diameter cylinder portion, said valve controlling admission of expanded motive fluid from said receiver through said passage to said large cylinder portion.

36. In a compound pneumatic impact tool, a small diameter and a large diameter cylinder, a small diameter and a large diameter piston reciprocable in said cylinder portions, a receiver, a passage from near the outer end of said small diameter cylinder portion to said receiver, a hollow valve in alinement with the piston and through which one oi the diameters travels, said valve intermittently admitting motive fluid to the small diameter cylinder portion, a passage from said receiver to the inner end of the large diameter cylinder portion, said valve controlling admission of expanded fluid from said receiver through said passage to said cylinder portion, and a passage between the opposite ends of said cylinder portion also controlled by said valve.

in a compound pneumatlc impact tool, a small diameter and a large diameter cylinder portion, a small diameter and a large diameter piston reciprocable in said cylmder port-ions, a hollow valve in alinement with the piston and through which one of the diameters of said piston travels, said valve intermittently admitting motive fluid into said small diameter cylinder portion, a receiver, a passage from near the end of said small. diameter cylinder portion to said receiver, a passage connecting the receiver and the inner end of the large diameter cylinder portion, said valve controlling said passage and also the exhaust from the inner end 51? said large cylinder portion, and a )assage connecting the opposite ends of said cylinder portions and controlled by said valve.

38. In a compound pneumatic impact tool, a barrel having its "forward end open and adapted to receive the shank of the working tool, said barrel having bores of different diameters, pistons of different areas in said bores, a receiver, a hollow valve in alinement with said pistons and through which one of said pistons travels, said valve connecting opposite ends of said bores to allow expanded and exhausted fluid from a small diameter bore to pass to said receiver and therefrom to act against the differential piston areas.

39. In a compound pneumatic impact tool, a barrel provided with a differential piston chamber having its front end open to receive the shank of the working tool, a differential piston in said chamber, a hollow valve in alinement with said piston and through which said piston travels and serving as a high pressure inlet controlling valve and as a low pressure exhaust controlling valve, and a receiver coacting with said valve and piston chamber and adapted to receive expanded air from one portion of said chamber and distribute it to another portion of said chamber.

40. In a compound pneumatic impact tool, a barrel having its forward end open to receive the shank of the working tool and provided with a differential piston chamber, whereby a high pressure and a low pressure cylinder is formed, a differential piston having a low pressure piston area therein, a receiver adjacent said cylinder and communicating with it at different points to permit expanded air to pass from said piston chamber to said receiver and thence to said piston chamber, a hollow valve through which said piston travels, means controlled by said valve for eni-tbling the exhaust from said low pressure cylinder to pass to the atmosphere, and means controlled by said valve for simultaneously placing the high pressure cylinder and the chamber beyond said low pressure piston into communication, so that the pressure of the two chamhers is equalized, whereby the inward stroke of said piston is effected.

all. In a compound pneumatic impact tool, a barrel having its forward end open to receive the shank of the Working tool and provided with a dilferential piston chamber forming a high pressure and a low pressure cylinder, a differential piston therein, a receiver adjacent said cylinder and communieating with said high pressure cylinder and said low pressure cylinder, a hollow controlling valve through which said piston passes, means controlled by said valve for enabling exhaust from said low pressure cylinder to pass to the atmosphere, and means controlled by said valve for placing the high pressure cylinder into communication with the chamber beyond the low pressure piston to equalize the pressure in such chambers, said valve also controlling the inlet to and exhaust from said high pressure cylinder of motive fluid, and said valve also controlling the passage of expanded air from said high pressure cylinder to said receiver and thence to said low pressure cylinder.

i2. In a compound pneumatic impact tool, a barrel having adifferential piston chamber forming a .high and a low pressure cylinder, the forwarr end of which is open for the reception of the shank of the working tool, a differential plunger in said piston chamber having pistons of different areas, a receiver, and a single hollow controlling valve through which said piston is adapted to pass, said valve admitting air at initial pressure to the high pressure cylinder and forming high pressure and low pressure cylinders, a receiver adapted to receive the expanded fluid from the high pressure cylinder and retain it for use when required in the low pressure cylinder, a differential pis-- ton, and a hollow controlling valve for said cylinders and receiver and through which said piston travels.

44. In a compound pneumatic impact tool,

- a barrel having its forward end open for the shank of the working tool and provided with a differential piston chamber, whereby high pressure and low pressure cylinders are formed, a reciprocatory piston in said cylinders, a receiver adapted to receive the expanded fluid from the high pressure cylinder and retain it for use when required in the low pressure cylinder, a single control-- ling valve in said piston chamber and throughwhich said piston travels, ports and passages common to said valve, receiver, and piston chamber, and means for causing live motive fluid pressure to constantly act upon a portion of said valve to shift it.

45. In a compound pneumatic impact tool, a barrel having therein a differential piston chamber, a differential plunger located in said piston chamber and having piston areas of different diameters, a hollow valve in said piston chamber for controlling the inlet and exhaust of motive fluidto and from said piston chamber and through which said piston passes, and means for causing live motive fluid to act constantly upon an end of said valve for shifting the same. i

46. In a compound pneumatic impact tool, a barrel having its forward end open to receive the shank of the Working tool and having a differential piston chamber therein, a differential plunger located in said piston chamber and having pistons of different diameters, a receiver communicating with said piston chamber at different points, a hollow VEIIXG in said piston chamber for controlling the inlet and exhaust of motive fluid to and from said piston chamber and.

through which said piston passes, and means for causing live motive fluid to act constantly upon an end of said valve for shifting the same and said valve controlling the distribution of expanded air from said piston chamber to said receiver and thence to said piston chamber.

47. In a compound pneumatic impact tool, a barrel having therein a differential piston chamber, a differential plunger located in said piston chamber and having piston areas of different diameters, a receiver communicating with said piston chamber at different points, a valve mechanism for controlling the inlet and exhaust of motive fluid to and from said piston chamber, said valve mechanism comprising a single valve located in the piston chamber and through which the piston travels, means for causing live motive fluid to constantly act upon one end of said valve for shifting the same, and means for effecting intermittent pressure and exhaust on the other end of said valve and said valve controlling the passage of expanded air from said piston chamber to said receiver and thence to said piston chamber.

48. In a compound pneumatic impact tool, a barrel having its forward end open for the reception of the shank of the working tool, said barrel having therein a differential piston chamber, a differential plunger located in said piston chamber, a receiver communicating with said piston chamber at different points, a single valve located in the piston chamber and through which the piston passes and controlling the reciprocations of said piston, and means for causing live motive fluid to act constantly uponan end of said valve for the purpose of shifting it, and said valve controlling the passage of expanded air from said piston chamber to said receiver and thence to said piston chamber.

49. In a compound pneumatic impact tool,

' a barrel having its forward end open for the reception of the shank of a working tool, said barrel having therein a differential piston chamber, a differential piston located in said piston chamber, a hollow valve in said piston chamber for controlling the reciprocations of the piston and through which said piston passes, means for causing live motive fluid to act constantly upon an end of said valve, a receiver, and ports and passages common to said valve, receiver, and piston chambers.

50. In a compound pneumatic impact tool, a barrel having its forward end open for the reception of the shank of the working tool,

said barrel having therein a differential piston chamber, a differential piston in said chamber, a valve in the piston chamber for controlling said piston and through which saidpiston passes, means for causing live motive fluid to act constantly upon an end of said valve, a receiver, and connections common to said receiver, piston chamber and valve whereby motive fluid is admitted from said receiver to act expansively upon a low pressure area of said piston simultaneously with the admission of live motive fluid to the high pressure area of said piston to augment the momentum of the striking blow of said piston.

51. In a compound pneumatic impact tool, a barrel having its forward end open to receive the shank of the working tool, a plurality of working cylinder portions of different diameters, a working plunger having pistons of different diameters reciprocable in said cylinder portions, a single valve for admitting motive fluid to small diameter cylinder portions and through which said piston travels, a plurality of receivers connected together, and means controlled by said piston for admitting expanded motive fluid from one of said cylinders to such receivers, said valve admitting expanded 1notive fluid from said receivers to the cylinder portion of larger diameter to augment the blow of the piston.

52. In a compound pneumatic impact tool, a barrel having a high pressure and a low pressure cylinder therein in axial alinement with each other, a. receiver formed by a longitudinalbore in said barrel, a piston having high and low pressure areas thereon and reciprocable in said cylinder, a grasping handle secured to said barrel, and a single valve through which said piston travels, said valve controlling ports common to said barrel and receiver.

In a compound pneumatic impact tool, a barrel having high and low pressure cyl inders therein, a receiver formed in said barrel, a piston conforming to said cylinders, and a single valve through which said piston travels, said valve controlling the admission and exhaust of motive fluid into the cylinder.

54:. In a compound pneumatic impact tool, a barrel having high and low pressure cylinders therein, a receiver formed in said barrel, a piston conforming to said cylinder. a grasping handle secured to said barrel, and a single hollow valve through which said piston travels and controlling the admission and exhaust of motive fluid in each of said cylinders.

55. In a compound pneumatic impact tool, a high pressure cylinder, a low pressure cyl. inder, a piston conforming to such cylin ders, and a valve consisting of a cylindrical shell located in one of said cylinders and adapted to have the piston pass through it and provided with opposing pressure areas against which the motive fluid acts to shift the valve in opposite directions.

56. In a compound pneumatic impact tool, a high pressure cylinder, a low pressure cylinder, a piston conforming to such cylinders, a valve consisting of a cylindrical shell located in one of said cylinders and adapted to have the piston pass through it and provided with opposing pressure areas against which the motive fluid acts to shift the valve in opposite directions, and means coacting with said valve to utilize the energy left in the motive fluid after it has been initially used in one cylinder for augmenting the energy of said piston.

57. In a compound pneumatic impact tool, a high pressure cylinder and a low pressure cylinder, a reciprocatory piston in said cylinders and a valve for controlling the movements of the piston and consisting of a cy' lindrical shell located in one of said cylinders and adapted to have the piston pass through it and provided with opposing pressure surfaces of different areas against the smaller of which the motive fluid constantly acts to press the valve in one direction and 'to the larger of which the motive fluid is intermittently admitted to move the valve in the opposite direction.

58. In a compound pneumatic impact tool, a high pressure cylinder, a low pressure cylinder, a reciprocatory piston in said cylinders, a valve located in the piston chamber and consisting of a cylindrical shell through which the piston passes and provided with differential pressure areas against the smaller of which the motive fluid constantly acts to press the valve in one direction, and a passage controlled by the piston for intermittently admitting the motive fluid to the larger pressure area of the valve to move it in the; opposite direction.

59. In a compound pneumatic impact tool, a high pressure cylinder, a low pressure cylinder, a. reciprocatory piston in said cylinders, a valve located in the rear end of one of said cylinders and consisting of a cylindrical shell through which the rear end of the piston passes at the end of its rearward stroke and provided with differential pressure areas against thesmaller of which the motive fluid constantly acts to press the valve in one direction, and a passage controlled by the piston and opened by the latter during its forward stroke to admit 'motive fluid to the larger area of said valve.

60. In a compound pneumatic impact tool, a. high pressure and a low pressure cylinder forming a piston chamber, a reciprocatory valve in said piston chamber, a valve located in the rear end of the piston chamber and consisting of a cylindrical. shell through which the rear end of the piston passes at the end of its rearward stroke and provided with differential pressure areas against the smaller of which the motive fluid constantly acts to press the valve forward, and a passage controlled by the piston and opened by the latter at its forward stroke to admit motive fluid for the larger area of the valve to move the valve rearward.

61. In a compound pneumatic impact tool, a high pressure and a low pressure cylinder forming a piston chamber, a piston in said piston chamber and a valve located in the rear end of the piston chamber consisting of a cylindrical shell through which the piston travels and provided with differential pressure areas against the smaller of which motive fluid constantly acts to press the valve forward, said piston controlling the admission of motive fluid to move the valve rearward, said valve when moved forward opening an annular port around its rear end to admit motive fluid to the rear end of the piston chamber and when moved in the opposite direction opening a passage leading from the high pressure cylinder to the front end of the low pressure cylinder.

62. In a compound pneumatic impact tool,

a high pressure and a low pressure cylinder forming a piston chamber, a piston in the piston chamber, a valve for controlling the piston and consisting of a cylindrical shell located in the piston chamber and adapted to have the piston pass through it and provided with differential pressure areas against which the motive fluid acts to shift the valve in opposite directions, and an exhaust passage leading from the larger area of said valve and opened by said piston at its rearward stroke.

68. In a compound pneumatic impact tool, a high pressure and a low pressure cylinder forming a piston chamber, a piston in the piston chamber, a valve through which the piston travels and having differential pressure areas against the smaller of which live motive fluid constantly acts to press the valve in one direction, a live air passage leading directly from the source of supply to the piston chamber, and a passage leading from the piston chamber to the larger area of the valve, said piston operating to close communication between said passages except when it approaches one end of its stroke and then place said passages in communication with each other to thereby admit motive fluid to the larger area of the valve.

64. In a compound pneumatic impact tool, a high and a low pressure cylinder forming a piston chamber, a piston in the piston chamber, a valve through which the piston travels and having differential pressure areas against the smaller of which live motive fluid constantly acts to press the valve in one direction, a live air passage leading directly from the source of supply to the piston chamber, a passage leading from the piston chamber to the larger area of the valve, a piston operating to close communication between said passages except when it approaches one end of its stroke and then place said passages in communication with each other to thereby admit motive fluid to the larger area of the valve, and an exhaust passage from the larger area of the valve opened by said piston at the forward end of its stroke.

65. In a compound pneumatic impact tool, a barrel having a, high pressure and a low pressure cylinder therein forming a piston chamber, a valve casing in the end or said barrel and having a longitudinal bore forming a continuation of the piston chamber, a reciprocatory piston, and a valve located in said valve casing and consisting of a cylindrical shell adapted to have the piston travel through it and provided with opposing pressure areas through which motive fluid is admitted to shift the valves in opposite directions.

66. In a compound pneumatic impact tool, a barrel having a high pressure and a low pressure cylinder therein forming a piston chamber, a valve casing at the end of the barrel and having a longitudinal bore forming a continuation of the piston chamber, and a valve located in said casing and consisting of a cylindrical shell adapted to have the piston pass through it and provided with differential pressure areas to the smaller of which motive fluid is constantly admitted, and to the larger of which motive fluid is intermittently admitted by 'a passage controlled by the piston. I

67. In a pneumatic impact tool, a cylinder, a hammering piston therein, a valve through which the piston passes, a receiver and means of augmenting the air pressure required for operating said piston and valve by motive fluid from a passage or chamber connected with said receiver and forming a part thereof, and controlled means for admitting live air which passes through said receiver.

68. In combination with a pneumatic impact tool, a receiver and passages and chambers connected with the receiver through which all the motive fluid passes and means for cushioning the recoil of the hammering plunger by the pressure of the motive fluid derived from such chamber or passage aforesaid.

69. In a pneumatic impact tool, a valve having the external annular grooves 26, 27 and 28 and the external rings 67, 68, 69 and 29, a receiver, a piston having differential pressure areas, and ports and passages common to said valve, receiver and piston, whereby air expanded during one stroke of said piston is distributed to said receiver and is utilized to augment the energy of said piston on its working stroke.

70. In combination with a pneumatic impact tool, a piston, a receiver, a valve through which the piston passes, and means for cushioning the recoil of said piston by live motive fluid derived from a chamber or passage in constant communication with the receiver and forming a part thereof.

71. In combination with a pneumatic impact tool, a piston, a receiver, a valve through which the piston passes, and means for cushioning the recoil of the inserted tool by live motive fluid derived from a chamber or passage in constant communication with the receiver and forming a part thereof.

72. The herein described valvefor a compound pneumatic tool, comprising a cylindrical shell having external grooves 26, 27 and 28, the external rings 67, 68, 69, 29 and the annular groove 81 at one end, said ring 29 being located at one end of the valve and being of greater external diameter than said other rings and the bore of said shell being of uniform diameter throughout its length.

73. The herein described valve, comprising a cylindrical shell having the annular grooves 26, 27 and 28 and the rings 67, 68, 69 and 29, said ring 29 forming a pressure area at one end of the valve different from the pressure area at the other end of the valve.

74. In a pneumatic impact tool, a piston therein, a valve through which said piston passes, a receiver, means for admitting live or expanded air to said receiver, and means 'for operating said valve by live motive fluid derived from a chamber or passage in constant communication with the receiver and forming a part thereof.

75. The herein described valve, comprising a cylindrical shell having the annular grooves 26, 27 and 28 and the rings 67 68, 69 and 29, in combination with means to exert pressure of live motive fluid against the ring 67 to advance the valve and to effect the expansion of the motive fluid and to exert the pressure of expanded motive fluid against the ring '29 to return the valve.

76. In a device of the character stated, a barrel, a grasping handle connected therewith, a high pressure and a low pressure cylinder in said barrel, a piston in said cylinders, a passage common to said barrel and handle to conduct expanded motive fluid from the high pressure cylinder to the low pressure cylinder to effect the return of the piston, and a single means to admit live motive fluid into the high pressure cylinder to advance the piston.

77. In a penumatic tool, a grasping han- "dle, a valve casing, a barrel having a plurality of cylinders therein, means to secure the handle, valve casing and barrel in assembled position, a piston in said cylinders, a single valve in the valve casing, a passage controlled by the valve and leading from one cylinder through the handle and communicating with the other cylinder to effect the travel of the piston in one direction, and means to introduce motive fluid into said cylinders to effect the travel of said valve in the opposite direction.

78. In a penumatic tool, a grasping handle, a valve casing, a barrel having a plurality of cylinders therein, means .to secure the handle, valve casing and barrel in assembled position, a piston in said cylinders,

a single valve in the valve casing, a passage controlled by the valve and leading from one cylinder through the handle and communicating with the other cylinder to effect the travel of the piston in one direction,

means to introduce motive fluid into said cylinders to effect the travel of said valve in the opposite direction, said valve being moved in one direction by live motive fluid, and in the opposite direction by expanded motive fluid in one -of said cylinders.

79. In a pneumatic impact tool, a piston therein, a valve through which said piston passes, a receiver, means for operating said piston by live motive fluid derived from a chamber or passage in constant communication with the receiver and forming a part thereof, and means for operating said valve by motive fluid which does not pass through the receiver.

80. In a penumatic impact tool, a piston therein, a valve through which said piston passes, a receiver, means for operating said valve by live motive fluid derived from a chamber or passage in constant communication with the receiver and forming a part thereof, and means for operating said piston by motive fluid which does not pass through the receiver.

81. In a pneumatic impact tool, a piston, a valve through which said piston passes, and means for absorbing the recoil of the inserted tool by pneumatic pressure by live motive fluid derived from a chamber or passage in constant communication with the receiver and forming a part thereof.

82. In a pneumatic impact tool, a piston, a valve through which said piston passes, and a receiver in constant communication with a chamber or passage forming a part thereof through which passes all the motive fluid necessary to operate the piston and valve.

8?). In a pneumatic impact tool, a cylinder, a piston therein, a valve through which said piston passes, a receiver through which part of the motive fluid passes and means for operating said piston and valve through which the piston passes by the pressure of the motive fluid from a chamber or passage in constant communication with the receiver and forming a part thereof.

84. In a pneumatic impact tool, a cylinder, a piston therein, a valve through which said piston passes, a chamber or passage in constant communication with the receiver and forming a part thereof, through which the motive fluid passes and means for operating said valve by a variation of the opposing pressures "on the same.

85. In a pneumatic impact tool, a cylinder, a valve through which the piston passes, a chamber or passage in constant communication with the receiver and forming a part thereof, and a piston with two or more diameters to receive the working fluid pres sure on its striking stroke. I

86. In a pneumatic impact tool, a cylinder, a piston, a valve through which the piston passes, a plurality of receivers and a chamber or passage in constant communication with such receivers and forming a part thereof, through which the motive fluid passes for theoperation of the various reciprocatory parts.

87. In a pneumatic impacttool, a cylinder, a piston, a valve through which the piston passes, and a plurality of receivers through which part of the motive fluid passes for operation of the various reciprocatory parts.

88. In a pneumatic impact tool, a cylinder, a piston, a valve through which .the piston passes, and a plurality of receivers through each of which the motive fluid passes for operation of the-various reciprocatory parts.

89. In a pneumatic impact tool, the combination of a piston, a cylinder, a handle, a valve through which said piston passes, a plurality of receivers and means for operating the tool by motive fluid from a chamber or passage in constant communication with the receivers and forming a part thereof.

90. In a pneumatic impact tool, the combination of a piston, a cylinder, a handle, a receiver, a valve through which said piston passes, and means for supplying the receiver with live motive fluid during the returning stroke of the piston. i

91. In a pneumatic impact tool, the combination of a piston a cylinder, a handle, a valve through which said piston passes, a receiver and a chamber or passage in constant communication with the receiver and forming a part thereof, through which all the motive fluid passes, and means for exhausting the motive fluid used for returning said piston after its striking blow.

92. In combination with a pneumatic impact tool, a receiver, and a chamber or passage in constant communication with thereceiver and forming a, part thereof through which all the motive fluid passes and means for cushioning the recoil of the hammerin plunger, and the recoil of the inserted too by such motive fluid.

93. In a pneumatic impact tool, a cylinder, a piston, a valve through which the piston passes, a receiver and means for operating said piston and valve through which the piston passes by the medium of the pressure of the motive fluid from a chamber or passage in constant communication with the receiver, and forming a part thereof.

94. In a pneumatic impact tool, a cylinder, a piston, a handle, a valve chamber, a

valve through which the piston passes, 'a receiver and means for supplying motive fluid from a chamber or passage in constant communication with the receiver, and forming apart thereof for operation of piston and valve. 1

95. Ina'pneumatic impact-tool, a cylinder, a piston, a handle, a valve chamber, a valve, a receiver and means forsupplying motive fluid from a chamber or passage in constant communication with a receiver, and forming a part thereof for operation of one or more of the reciprocatory parts.

96. In a pneumatic impact tool, a piston, a valve through which the piston passes, a receiver, and means for supplying motive fluid from a chamber or passage in constant communication with the receiver, and forming a part thereof for operating one or more of the reciprocatory parts.

97. In a compound pneumatic tool, with cylinders of different diameters, a piston slidable in same, a valve chamber, a single valve through which the piston passes, a plurality of receivers cooperating with said cylinder and means for supplying motive fluid from a chamberor passage in constant communication with the receiver, and forming a part thereof for operation of the reciprocatory parts.

98. A pneumatic impact tool comprising a cylinder, a piston therein, a single valve through which the piston travels, a receiver, and means for operating said piston by means of pressure of motive fluid from a chamber or passage in constant communication with the receiver and forming a part thereof.

99. In a pneumatic impact tool, a cylinder, a piston, a valve through which the piston passes, an intermediate hammering block, a receiver and means for supplying motive fluidfrom a chamber or passage in constant communication with the receiver and forming a part thereof for operating one or more of the reciprocatory parts.

100. In a pneumatic impact tool, a cylinder, apiston, a valve through which the piston travels, an intermediate hammering block, a plurality of receivers cooperating with said cylinder and means for supplying motive fluid from a chamber or passage in constant communication with the receivers and forming a part thereof, from the receivers for operating one or more of the reciprocatory parts. I

101. In a pneumatic tool, a cylinder, a piston, a valve through which the piston passes, a receiver and means for supplying motive fluid from a chamber or passage in constant communication with the receiver and forming a part thereof, for operating one or more of the reciprocatory parts.

102. In a pneumatic impact tool, a cylin der, a piston, a'valve'through which the piston passes, a receiver, means for supplying motive fluid from a chamber or passage in constant communication with the receiver and forming a part thereof for operating one or more of the reciprocatory parts and means for forming a cushion of air at back of piston on its return stroke.

103. In a pneumatic impact tool, a cylinder, a piston, a valve through which the piston passes, a receiver and chambers or passages connected therewith and forming a part thereof through which the motive fluid passes, and means for forming an air cushion with a part of said motive fluid back of the piston on its return stroke.

104. In a pneumatic impact tool with cylinders of different diameters, a piston slidable in same, a valve chamber, a single valve, a receiver common to all cylinders, and means for supplying motive fluid from a chamber or passage in constant communi cation with the receiver and forming a part thereof, for operation of the reciprocatory parts.

105. In a pneumatic impact tool with cylinders of different diameters, a piston slidable in same, a valve chamber, a single valve, a receiver for each cylinder and means for supplying motive fluid from a chamber or passage in constant communication with the receiver and forming a part thereof for operation of the reciprocatory parts.

106. In a pneumatic impact tool, the combination of a piston, a cylinder barrel, a handle, a valve chamber, a valve through which the piston travels and a plurality of receivers having chambers or passages connected therewith and forming a part thereof, through which the motive fluid passes for the operation of the tool.

107. A pneumatic impact tool, comprising a barrel, a smalldiameter cylinder, a large diameter cylinder, a piston adapted to re ciprocate in said cylinders, a single valve for controlling distribution of motive fluid and through which said piston passes, and means coacting with said single valve for supplying a mixture of live and expanded motive fluid from the receiver to operate the reciprocatory parts.

108. A pneumatic impact tool comprising cylinders of several diameters, a receiver having chambers or passages connected therewith and forming a part thereof for either live, expanded or mixed motive fluid at will, a reciprocatory piston in said cylinders having differential piston areas the sum of the pressure on the rear working faces from the receivers or the chambers connected therewith as a part thereof causing the striking blow.

109. A pneumatic impact tool, comprising a barrel, cylinders therein, a reciprocatory piston in said cylinders, a receiver and a single valve through which the piston passes for controlling the flow of the motive fluid to and from said cylinders and into and from said receiver.

110. A pneumatic impact tool, comprising a plurality of cylinders of varying diameters, pistons of varying diameters fitted to reciprocate in said cylinders, a receiver connected to receive motive fluid having chambers or passages connected therewith through which the motive fluid passes for the operation of the tool by simultaneous pressure on the rear faces of the piston, passages adapted to connect said receiver with end of large diameter cylinder, and a single valve adapted to have one of said pistons pass through it and adapted to control the flow of motive fluid to said small diameter cylinder.

111. A pneumatic impact tool, comprising a small diameter cylinder, a large diameter cylinder, a small and large diameter piston adapted to reciprocate therein, a receiver connected to receive live motive fluid during the return stroke of the hammering piston and a single valve through which the piston travels and adapted to control the flow of the motive fluid to the small and large diameter cylinder and to the receiver for returning the piston.

112. A pneumatic impact tool, comprising a small diameter and a large diameter cylinder, a piston having a small and large diameter respectively reciprocating in said cylinders, a receiver having a passage for supply of motive fluid, and a single valve through which the small diameter of the piston passes, said valve controlling the flow of the live motive fluid to the inner end of the small diameter cylinder and the flow of the motive fluid from the receiver to the inner face of the large diameter piston.

118. A pneumatic impact tool, comprising a barrel, cylinders of varying diameters, a piston of varying diameters respectively reciprocable in said cylinders, a receiver, a single valve through which one diameter of said piston passes, said valve being connected to intermittently admit motive fluid at the inner end of each diameter cylinder from said receiver to drive said piston outwardly, and said valve being reciprocated by suitable means at predetermined periods during the stroke of the piston.

114:. A pneumatic impact tool comprising a barrel, small diameter and large diameter cylinders therein, a piston having small and large diameter portions respectively reciprocable in said cylinders, a receiver connected to receive motive fluid having a chamber or passage connected therewith and a part thereof, through which the motive fluid passes for the operation of the tool, a valve chamber, and a single valve in said valve chamber through which the small diameter piston passes and adapted to control the distribution of motive fluid to said small cylinder and said large cylinder.

115. A pneumatic impact tool, comprising a barrel, small diameter and large diameter cylinders therein, a piston having small and large diameter portions reciprocal in said cylinders, a receiver connected to receive the motive fluid, having a chamber or passage connected therewith and a part thereof through which the motive fluid passes for the operation of the tool, a single valve chamber, a single valve reciprocal in said chamber to intermittently admit motive fluid at the inner end of said small diameter cylinder and to intermittently connect the inner ends of said large diameter cylinder to exhaust and said valve adapted to have the small diameter portion of said piston travel therethrough.

116. A pneumatic impact tool, comprising a barrel, a small diameter and large diameter cylinder therein, a piston having small and large diameter portions respectively reciprocable in said cylinders, a receiver having a passage for supplying said cylinders with live motive fluid, a single valve chamber having an inlet for the motive fluid and ports connected to the inner ends of said cylinders and an exhaust, a single valve in said valve chamber adapted to admit motive fluid to the small diameter piston and motive fluid from the receiver to the inner portion of the large diameter piston and intermittently connect the inner end of the large diameter cylinder to an exhaust, said valve being adapted to have the small diameter portion of the said piston travel therethrough and being actuated in, alternate directions by variation of opposing pressures.

117. A pneumatic impact tool, comprising a barrel having its forward end open'to receive the shank of the working tool and hav ing cylinders of different diameters, a piston having portions of different diameters, to reciprocate in said cylinders, a receiver having a chamber or passage connected therewith and a part thereof through which the motive fluid passes for the operation of the tool, a single valve through which one of the diameters of the piston travels, said valve effecting the simultaneous admission of motive fluid from receiver to each cylinder and the simultaneous exhaust from each cylinder.

118. In a compound pneumatic tool, a barrel, a high pressure and a low pressure cylinder therein, a piston in said cylinders, a valve casing, a receiver formed in said barrel and casing, and a valve in the valve casing and consisting of a cylindrical shell adapted to have the piston pass through it and provided with opposing pressure areas against which motive fluid acts to shift the valve in opposite directions, said valve cooperating with the high and low pressure cylinders and the receiver to control admission to motive fluid to the cylinders and the exhaust therefrom.

119. The herein described valve casing, comprising a body portion having an aperture therethrough, annular ports 33, 58, 40, 37, 53, 43 and 30, and provided with a receiver 36, in combination with a valve movably mounted in said aperture and controlling said ports.

120. The herein described valve casing, comprising a body portion having a bore therethrough with annular ports 33, 58, 40, 37, 53, 43, passages 41, 42, 45, 47 and 63, a sleeve surrounding said body portion and contributing therewith to form a receiver 36, in combination with a valve controlling all of said ports and passages except the passage 47 which latter is adapted to control admission of motive fluid to reverse the position of the valve.

WILLIAM BURLINGHAM.

Vitnesses L. O. BRANCH, MoG. LINTON. 

